The invention relates to an active vibration damper for a reciprocating machine part. The active vibration damper comprises an inertial mass that can be displaced in the direction of the reciprocating motion and a support plate that can be fastened to the machine part, a spring element being interposed between the inertial mass and the support plate.
A vibration damper of this kind is known from U.S. Pat. No. 5,236,186, the disclosure of which is incorporated herein by reference. The vibration damper is associated with a vibrating body made of magnetizable material that magnetically attracts a magnet, by which attraction the inertial mass can be set in motion. The magnet and the vibrating body can move relative to one another in any operating state. The magnet, which forms at least one part of the damping mass, and the vibrating body are separated by a gap that extends substantially transverse to the direction of the introduced vibrations. A spring element is interposed between the magnet and vibrating body. The configuration of this vibration damper is particularly advantageous in terms of cost and manufacturability; it is worth noting, however, that during its intended use, the gap between the return plate and the magnet continually changes, therefore causing nonlinear properties of the damper that are difficult to predict.